Positive Electrode Protective Layer for Uniform Short-Circuit Heat Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing secondary batteries face challenges in uniformly suppressing heat generation during internal short circuits, as conventional protective layers may not adequately distribute inorganic compounds, leading to insufficient heat management.
Innovation Solution
A positive electrode with a protective layer comprising secondary particles of an insulating inorganic compound and a conductive agent, where the median particle size of the secondary particles is 30 μm or less, is interposed between the current collector and the mixture layer, ensuring uniform dispersion and effective heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a protective layer with inorganic compound particles is formed between the current collector and mixture layer, then heat generation is suppressed, but uniform heat suppression throughout the positive electrode is insufficient
Solution Approach 1:
The inorganic compound particles are divided into primary particles (1 μm or less) that aggregate to form secondary particles with a median size of 30 μm or less. This segmentation into controlled secondary particles ensures uniform distribution throughout the protective layer, addressing the insufficient uniform heat suppression while maintaining effective heat generation suppression.
Solution Approach 2:
The patent specifies precise parameter ranges: primary particle size of 1 μm or less, secondary particle median size of 30 μm or less, and inorganic compound content of 70-95 volume%. By controlling these parameters, the protective layer achieves homogeneous inorganic compound distribution, enabling reliable uniform heat suppression across the entire positive electrode.
2Object-generated harmful factors
If the protective layer includes inorganic compound particles, then redox reaction heat is suppressed, but the dispersibility and homogeneity of the inorganic compound are insufficient
Solution Approach 1:
The inorganic compound is processed into primary particles of 1 μm or less that naturally aggregate to form secondary particles. This segmentation approach improves dispersibility within the protective layer matrix, achieving homogeneous composition throughout the layer while maintaining the heat suppression function.
Solution Approach 2:
The protective layer is designed as a composite material containing inorganic compound particles (70-95 volume%), conductive agent (0.1-5 volume%), and binder (5-30 volume%). This composite structure ensures homogeneous distribution of the inorganic compound while maintaining electrical conductivity and mechanical integrity, preventing redox reaction heat generation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration significantly reduces heat generation during internal short circuits by ensuring uniform distribution of the inorganic compound and maintaining conductivity, thereby preventing temperature increases.
Implementation Method 1
heat generation when an abnormality such as an internal short circuit occurs may be suppressed
Implementation Method 2
a conductive agent, the protective layer includes secondary particles formed by aggregation of primary particles of the inorganic compound
Data Source
AI summary
This positive electrode includes: a positive electrode current collector; a positive electrode mixed material layer that is formed on at least one surface of the positive electrode current collector; and a protective layer which includes an insulating inorganic compound and a conductive material, and is interposed between the positive electrode current collector and the positive electrode mixed material layer. The protective layer includes secondary particles comprising agglomerated primary particles of the inorganic compound. The median value of the particle size of the secondary particles is 30 μm or less.